Double piston valveless pump or engine



w. F. CRENSHAW 2,495,445

DOUBLE PISTON VALVELESS PUMP 0R ENGINE Jan. 24, 1950 Filed Jan. '12, 1946 INVENTOR WILLIAM F. CRENSHAW ATTORNEY Patented Jan. 24, 1950 DOUBLE PISTON VALVELESS PUMP on ENGINE William F. Crenshaw, Lafayette, La.

Application January 12, 194.6, Serial No. 640,938

1 Claim. 1

This invention relates to new and useful improvements in a double piston valveless pump or engine.

More specifically, the present invention proposes the construction of a device which may be used as a ,pump, compressor or motor, and which is characterized by having a cylinder, a piston therein, a piston in the first piston, the two pistons reciprocating at right angles to each other, and a drive shaft with an "eccentric in the inner piston.

Still further, it is proposed to provide a device as aforesaid which is valveless.

Another object is to provide a device as aforesaid in which only one packed gland is needed.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

Fig. 1 is a side elevation of a device constructed in accordance with this invention.

Fig. 2 is a side elevation looking from the right side of Fig. 1.

Fig. 3 is a plan view of Fig. 1.

Fig. 4 is a section on the line 4-4 of Fig. 3.

Fig. 5 is a section on the line 5-5 of Fig. 1.

Fig. 6 is a section taken substantially on the line 6-6 of Fig. 1.

The device of the present invention may act as a pump, compressor-or motor (engine). Structurally, it has the same parts regardless of whether it drives its shaft by its piston or whether its piston is driven by its shaft. It will therefore be described in connection with its operation as a pump.

The pump, according to this invention, co prises a cylinder Ill having internal shoulders at its ends receiving heads ll closing the opposite ends of the cylinder. The cylinder is shown vertically in the drawings and will be so described. A piston 12 is disposed in the cylinder for vertical reciprocation therein. The piston has a horizontal cylindrical bore 43 in which isa recess It in the inner face of the cylinder in. This shaft l6 has an integral cylindrical eccentric i9. When the shaft I6 is rotated and the eccentric is rotated it moves the inner piston I back and forth in the large piston 12 and at the same time moves the large piston l2 up and down in the cylinder Ill.

The shaft i6 is packed in the orifice I! by a gland 20 which may be of any well known construction, the gland 20 and the cylinder heads ll tightly sealing the cylinder Ill against loss of lubricant or other fluids. This necessity of but a single gland adapts the device of the present invention for such uses as a sealed unit in a refrigerator.

The device is, as aforesaid, valveless. The cylinder is provided with an inlet port 2| and by .a diametrically opposite outlet port 22, these ports being in the side wall of the cylinder Ill. The various parts of the device are interconnected for fluid'fiow by an intricate system of ports which are as follows:

There is a port 23 in the top of the outer piston 12 communicating with a smaller port 24 in the top of the inner piston l4, port 24 communicating with the interior of the smaller piston. There is a port 25 in the side of the inner piston It also communicating with the interior thereof; and with a passage 26 in the eccentric Hi. There is another port 21 in the other side wall of the inner piston l4 and this, like the port 25, communicates with a passage 28 in the eccentric l9. Passages 26 and 28 communicate respectively with ports 29 and 30, also in the eccentric. Finally there is a port 3| in the inner piston l4 opposite port 24.

The operation of the pump is as follows:

Power is applied to the shaft 16. The eccentric I9 is rotated as the shaft rotates and moves the inner piston l4 back and forth and the large piston l2 up and down. Shaft l6 rotates clockwise, -and port 2! takes in fluid to be pumped while port 22' acts-as the outlet. When the large piston I2 is at dead center, the inner piston I4 is at mid-stroke and vice versa.

The outer piston l2 has a sliding movement in the cylinder l0, moving from one end of the cylinder to the other end, due to the eccentric l 9, which causes the inner piston Hi to slide from one end of the outer piston l2 to the other end thereof, or nearly so. The eccentric I9 on the shaft 18 thus produces reciprocation of the outer piston I! in the cylinder 10, from end to end, and reciprocation of the inner piston within the tubular outer piston.

The movement of the outer tubular piston in the cylinder l0 generates a suction impulse at one 2 end of the outer piston, and a compression impulse at the other end. The movement of the inner piston in the tubular outer piston also generates a suction impulse at one end of the inner piston and a compression impulse at the other end.

When the two pistons are in the position shown in Fig. 4, the inner piston will be moving to the left and the outer piston will move upwardly. Fluid will then be drawn through the intake port 2| to the chamber I3. As the eccentric 19 turns in the bore of the inner piston, it will uncover the port or passage 3| as it forces the outer piston l2 upwardly, and fluid will be forced through the passage 3| to the space between the lower end of the outer piston I2 and the cylinder l0. As the eccentric continues its rotation, the passages 21 and 28 will be placed in communication with each other and the fluid will be discharged above the outer piston, and thence discharged through the port 22 to any service connection coupled to this port.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the preclse constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claim.

Having thus described by invention, what I claim as new, and desire to secure by United States Letters Patent is:

An apparatus of the class described, comprising a one-piece cylinder having end walls closing the ends thereof and diametrically opposite inlet and outlet ports midway of the ends thereof, an outer piston slidable within said cylinder parallel to the longitudinal axis of said cylinder and formed with a. bore extending at right angles to the longitudinal axis of said cylinder, aninner piston slidable within the bore of said outer piston and formed with a bore extending at right angles to the bore of said'outer piston, said outer piston being formed at its ends with ports concentricv with the longitudinal axis of saidcylinder and in communication with complementary ports in the adjacent sides of said inner piston, said inner piston being formed at its ends with ports concentric with the axis of said bore of said outer piston, said inlet and outlet ports being in communication with the bore of said inner piston through openings formed in the sides of said outer piston at right angles to its bore, a shaft rotatively extended through one side wall of said cylinder midway of its ends, through said openings of said outer piston, through the bore of said inner piston and having its inner end rotatively supported within a recess formed in the inner face of the d'ametrically opposite wall of said cylinder, a cylindrical eccentric formed on said shaft within the bore of said inner piston for reciprocating said inner piston within the bore of said outer piston and for reciprocating said outer piston within said cylinder when said shaft is rotated, diametrically opposite ports formed in said eccentric for successively communicating with said side ports and said end ports of said inner piston as the eccentric rotates within said inner piston, and ports extending in opposite directions from the ports of said eccentric and extended through the opposite ends of said eccentric and ctmmunieating with the bore of said inner piston.

WILLIAM F. CRENSHAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

